1. Field of the Invention
The invention relates to a flip top cap for use with laboratory vessels, such as tubes.
2. Description of the Related Art
Many laboratory procedures require tissue cultures or cell cultures to be stored and/or cultivated in a vessel, such as a tube or a flask. The typical tube includes a cylindrical side wall, a closed bottom and an open top. The closed bottom often is conically generated. The size of the tube varies from one laboratory procedure to another, and tubes typically will define volumes from 15 mL to 50 mL. Flasks also have a side wall, a closed bottom and an open top. For simplicity, the following discussion will describe tubes, but pertains to other laboratory vessels as well.
Many laboratory procedures require the tissue or cell cultures in the tube to remain sterile. Thus, the tube typically is provided with a cap for sealing the open top of the tube. However, the cap must be removed periodically to access the tissue or cell cultures in the tube.
Many caps are formed separate from the tube and have a portion dimensioned for telescoping partly into the tube and sealing with the inner surface of the side wall adjacent the open top of the tube. These caps may be formed from an elastomer or other resilient material to ensure sealing with the tube. Other caps include a substantially rigid collar surrounding portions of the cap that telescope into the tube. The collar can be telescoped over the open top of the tube and provides a region that can be gripped conveniently for removing the cap from the tube.
Laboratory workers generally place the cap top-down on a laboratory work surface while they are accessing the interior of the tube with a pipette to obtain a sample of the cell or tissue culture in the tube. Thus, the side and bottom of the cap do not contact the potentially non-sterile work surface. The cap then is repositioned in sealing engagement with the open top of the tube after the cell or tissue culture has been accessed. These tube and cap combinations require the laboratory worker to use two hands to remove the cap. Additionally, these tube and cap combinations create the potential that the cap will be positioned improperly on the work surface, thereby creating the potential for contaminants being transferred from the work surface to the tissue or cell culture in the tube.
Some tubes have been manufactured with a flip cap to permit one-handed opening and to avoid the need to place any part of the cap on a laboratory work surface while the interior of the tube is being accessed by a pipette. These tube and cap assemblies typically include a body that is threaded or otherwise mounted to the open top of the tube. A cap is connected to the body by a hinge, such as a living hinge. A laboratory worker holds the tube between the forefingers and the palm of one hand. The thumb of the same hand then is urged against the cap to move the cap out of engagement with the body so that the cell or tissue culture in the tube can be accessed. These flip top caps provide certain handling efficiencies and avoid the need to place the cap on the work surface in the laboratory while the contents of the tube are being sampled. However, prior art flip top caps require the user's thumb to pass directly over the open top of the tube. There is a high probability that the user's thumb will contact the open top of the tube while the cap is being rotated away from the open top of the tube. Contact of the thumb with the open top of the tube is likely to contaminate the tube and the tissue or cell cultures stored therein.
In view of the above, it is an object of the subject invention to provide a tissue culture vessel, such as a tube, that can be opened easily without significant risk of contamination to the contents of the vessel.